What are lossy and lossless audio formats, and what are common audio formats? Part 2

Audio Formats:

2. WAVE is a sound file format developed by Microsoft, it is used to save the audio information resources of the WINDOWS platform, and is compatible with the WINDOWS platform and its applications.

3. AIFF format (Audio Interchange File Format) and AU format, AIFF is the English abbreviation for Audio Interchange File Format. It is an audio file format developed by APPLE and supported by the MACINTOSH platform and its applications. Many compression techniques are supported.

4.MPEG is the English abbreviation for Motion Picture Experts Group Currently, MP3 is the most common music format on the Internet. Although it is lossy compression, its biggest advantage is a higher compression ratio in exchange for very little sound distortion.

5. MP3 MPEG audio file compression is lossy compression. MPEG3 audio encoding has a high compression ratio of 10:1~12:1, while basically keeping the low audio part undistorted, but at the expense of the high 12KHz to 16KHz. in the sound file. The quality of the audio part is changed by the size of the file. Music files of the same length are stored in *.mp3 format, usually only 1/10 of *.wav file, so the sound quality is lower than CD or WAV format.

6. MPEG-4 Adopts object-based compression coding technology. Before encoding, the video stream is first analyzed, and each video object is segmented from the original image, and then the shape information, motion information, texture information is encoded separately, and temporal redundancy between consecutive frames is eliminated thanks to better motion prediction and compensation than MPEG-2. Its core is content-based scalability, which can assign priorities to each object in the image, express the most important objects with high spatial and temporal resolution, and express the less important objects (such as surveillance systems, background) are rendered. with a lower resolution. or even not displayed. Therefore, it has the ability to adaptively allocate resources and can perform low-speed, high-quality video transmission and image communications. It occupies less resources, has great flexibility, good network performance, and has a wider range of applications.

7. The MIDI (Musical Instrument Digital Interface) format is used by people who often play music, MIDI allows digital synthesizers and other devices to exchange data.

8. WMA (Windows Media Audio) format is a heavyweight player from Microsoft. The background is harsh, the sound quality is stronger than MP3 format, and it is much better than RA format. It is the same as the VQF format. developed by the Japanese company YAMAHA. However, the method to maintain sound quality can achieve higher compression ratio than MP3. The compression ratio of WMA can generally reach around 1:18. Another advantage of WMA is that content providers can use DRM (Digital Rights Management) like Windows Media. Rights Manager 7 adds copy protection.

What are lossy and lossless audio formats, and what are common audio formats?

We often hear some terms like MP3, lossless, CD sound quality, and even come into contact with them. So what are lossy and lossless audio formats? What are their differences? Apart from the ones I heard above, what other common audio formats exist? Next, I will share with you the relevant knowledge of audio formats and answer your questions.

First, let’s briefly popularize the audio format:

The audio format is the music format. Audio format refers to the process of digital and analog conversion of audio files for playback or processing on a computer. At present, music file playback formats are divided into two types: lossy compression and lossless compression. When using different music file formats, there is a big difference in sound quality performance.

Difference Between Lossy and Lossless Compression:

Lossy compression is to reduce the audio sample rate and bit rate, and the output audio file will be smaller than the original file. Lossless compression, on the premise of saving 100% of all the data in the original file, can compress the audio file to a smaller size, and after restoring the compressed audio file, it can achieve the same size and code. than the source file. Speed.

Here are the common audio formats:

1. CD The standard CD format is the sampling frequency of 44.1K, the rate is 1411K/second, and the quantization number is 16 bits. Since the CD track can be said to be approximately lossless, its sound is basically faithful to the original sound.

Lossy vs Lossless, Audio Quality

Much is said and has been said about the difference between the formats that generate a loss of information (lossy) versus those that do not generate any loss (lossless).

What is Lossy?

To compress a file, so that it occupies less space on the disk, we must necessarily use two techniques, the first is pure compression, which does not lose quality and which we will explain later PLUS compression by discarding information.

It is omitting information that we know, after studies, that the human ear will hardly perceive. At least the average human ear.
Younger people listen to more frequencies than from the age of 30, when we listen to fewer frequencies.

But not only does age count, but other phenomena also enter, for example what is called masking and which could be summarized by saying that if two frequencies occur with similar frequencies, and one occurs an instant before the other, in general the second that masked… that is, it is not audible to the human ear, so we could discard it and save space.

There are also all the frequencies that the human ear does not perceive, there we have more information that we can discard without damaging the quality or at least maintaining a very similar quality of perception.

LossLess

There are other formats that do not lose quality because they only use mathematical methods to save space. Imagine the following line:

1111111000001110000000

This consumes a space, but this information could be summarized, for example as follows:

1(7)0(5)1(3)0(7)

This second way of storing information takes up much less space WITHOUT discarding anything. It simply explains that from the number 1 there are 7, followed by 5 zero numbers, then 3 from the number 1 and finally 7 zeros.

It’s the same, we just tried to save space by finding a compressed way to write it, but we didn’t rule anything out.

This is exactly how the zip and lossless music methods work.

Is there a difference in the human ear when listening to one and the other?
We will answer that in another article.